September 9, 2022
2 min reading
Abdelrahman does not provide any relevant financial information. Please refer to the study for all relevant financial data of the authors.
The addition of 18-fluorodeoxyglucose to PET provided a significant prognostic benefit in the objective assessment of response to neoadjuvant chemotherapy in patients with borderline resectable/locally advanced pancreatic cancer.
Findings published in JNCCN — Journal of the National Comprehensive Cancer Network — may help in deciding whether to proceed with complex surgery, continue current treatment or consider a change in chemotherapy, the researchers noted.
Anatomic imaging by CT or MRI poorly predicts response to neoadjuvant therapy in patients with borderline resectable/locally advanced pancreatic ductal adenocarcinoma, and measurement of changes in carbohydrate antigen 19-9 (CA 19-9) markers yields inconsistent results and is often not possible. Although pathologic response is highly predictive of survival after neoadjuvant therapy, it is known only after surgery according to the background of the study.
For this reason, Amro M. Abdelrahman, MBBS, MS, postdoctoral researcher in the Department of Surgery at Mayo Clinic and colleagues sought to evaluate metabolic imaging with preoperative PET plus 18-fluorodeoxyglucose (18F-FDG) in 202 patients (mean age 64.7 years; 58% male; 92.6% white) with borderline resectable/locally advanced pancreatic cancer who received first-line neoadjuvant therapy with either modified FOLFIRINOX (leucovorin, 5-FU, irinotecan, and oxaliplatin) or gemcitabine and nab-paclitaxel (Abraxane, Bristol Myers Squibb).
Amro M. Abdelrahman
Investigators compared metabolic and biochemical responses after neoadjuvant therapy as preoperative predictors of pathologic responses, recurrence-free survival, and OS.
Most patients (58%) had optimal CA 19-9 levels after neoadjuvant therapy. Additionally, 51% had a major metabolic response and 38% had a major pathologic response. The researchers reported a median recurrence-free survival of 21 months and a median OS of 48.7 months.
Metabolic response appeared better than biochemical response in predicting pathologic response (area under the curve, 0.86 vs. 0.75; P < 0.001), highly correlated with pathologic response regardless of biochemical response (P = 0.001) and was the only univariate preoperative predictor of OS (OR = 0.25; 95% CI, 0.13-0.4).
Metabolic response remained the largest independent preoperative predictor (P < 0.001) for pathologic response (OR = 43.2; 95% CI, 16.9-153.2), recurrence-free survival (HR = 0.37; 95% CI, 0.2-0.6), and OS (HR = 0.21; 95% CI, 0.1 -0.4) in multivariate adjustment.
“Previously, we had to wait until after complex surgery to tell how pancreatic cancer responded to neoadjuvant therapy,” Abdelrahman said in a press release. “With FDG-PET, we can tell patients how the cancer has responded to neoadjuvant therapy before they undergo extensive surgical resection. Going forward, we recommend that providers combine all available measures on a case-by-case basis to make appropriate decisions about changes in neoadjuvant therapy and final decisions for surgery or no surgery.”
According to Abdelrahman and colleagues, an R01-funded clinical trial is underway at the Mayo Clinic to further study the use of PET to assess treatment response in pancreatic ductal adenocarcinoma.
“Although prospective studies are warranted, FDG-PET results for [this patient population] in this study may be sufficient to recommend FDG-PET as an approved adjunctive modality in evaluating the efficacy of neoadjuvant therapy in addition to currently approved but poorly predictive metrics,” the researchers wrote. “We recommend that providers combine all available measures of response (ie, clinical, radiologic, biochemical, and metabolic) to make appropriate decisions regarding changes in neoadjuvant therapy and final decisions for surgery or no surgery on a case-by-case basis.”
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